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Measurements of the Neutral Current ep Cross Sections Using Longitudinally Polarised Lepton Beams at HERAII
Measurements of the Neutral Current ep Cross Sections Using Longitudinally Polarised Lepton Beams at HERAII
This thesis presents inclusive $e^\pm p$ single and double differential cross sections for neutral current deep inelastic scattering measured as functions of the four-momentum transfer squared $Q^2$ and the Bjorken variable $x$ in interactions of longitudinally polarised leptons with unpolarised protons using the H1 detector at HERA~II. An overview of the phenomenology of deep inelastic scattering is given and the experimental apparatus as well as the measurement and analysis procedures are described. The analysis is based on $e^+p$ data taken in 2003-04 and $e^-p$ data taken in 2005 at a centre-of-mass energy of $\sqrt s = 318$~GeV, with integrated luminosities of 47.6~pb$^{-1}$ and 98.4~pb$^{-1}$ for the $e^+ p$ and $e^- p$ samples, respectively. The cross sections are measured in the range of $200 < Q^2 < 20\,000$~GeV$^2$ and $0.0032<x<0.65$. The measurements are used to study polarisation effects in neutral current interactions and to determine the structure function $x\tilde{F}_3$. The new HERA~II data are combined together with previously published data from HERA~I to determine the structure function $x\tilde{F}_3$ with improved precision. Furthermore, this measurement is combined with the corresponding ZEUS measurement to provide the most accurate measurement of the interference structure function $xF_3^{\gamma Z}$, which is sensitive to the valence quark distributions down to low values of $x$. The data on polarised cross section asymmetries $A^\pm$ are also combined with the ZEUS data. This leads to the first observation of parity violation in neutral current $e^\pm p$ scattering at distances down to $10^{-18}$~m. The data are well described by the Standard Model predictions.
Deep inelastic scattering, neutral currents, polarisation asymmetry, structure functions
Nikiforov, Andriy
2007
English
Universitätsbibliothek der Ludwig-Maximilians-Universität München
Nikiforov, Andriy (2007): Measurements of the Neutral Current ep Cross Sections Using Longitudinally Polarised Lepton Beams at HERAII. Dissertation, LMU München: Faculty of Physics
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Abstract

This thesis presents inclusive $e^\pm p$ single and double differential cross sections for neutral current deep inelastic scattering measured as functions of the four-momentum transfer squared $Q^2$ and the Bjorken variable $x$ in interactions of longitudinally polarised leptons with unpolarised protons using the H1 detector at HERA~II. An overview of the phenomenology of deep inelastic scattering is given and the experimental apparatus as well as the measurement and analysis procedures are described. The analysis is based on $e^+p$ data taken in 2003-04 and $e^-p$ data taken in 2005 at a centre-of-mass energy of $\sqrt s = 318$~GeV, with integrated luminosities of 47.6~pb$^{-1}$ and 98.4~pb$^{-1}$ for the $e^+ p$ and $e^- p$ samples, respectively. The cross sections are measured in the range of $200 < Q^2 < 20\,000$~GeV$^2$ and $0.0032<x<0.65$. The measurements are used to study polarisation effects in neutral current interactions and to determine the structure function $x\tilde{F}_3$. The new HERA~II data are combined together with previously published data from HERA~I to determine the structure function $x\tilde{F}_3$ with improved precision. Furthermore, this measurement is combined with the corresponding ZEUS measurement to provide the most accurate measurement of the interference structure function $xF_3^{\gamma Z}$, which is sensitive to the valence quark distributions down to low values of $x$. The data on polarised cross section asymmetries $A^\pm$ are also combined with the ZEUS data. This leads to the first observation of parity violation in neutral current $e^\pm p$ scattering at distances down to $10^{-18}$~m. The data are well described by the Standard Model predictions.